In a move that has shocked both major political parties and the Conservatives, the alleged Conservative leader, Iain Duncan "Smith", was this morning revealed as the new contestant for "hit" reality TV show Big Brother.

After three years as Channel Four's most bankable project, Big Brother has run into trouble this year following dramatically reduced viewing figures. As even Graham Norton's interest starts to wane, Channel Four has attempted to revitalise the show through a variety of high-profile publicity stunts, including Viagra-laced drinking water, alleged tabloid "scandals" and a much-hyped "bomb scare" last Friday.

"We couldn't take any risks," noted police explosives expert Brandon Scott Jackson on Saturday, "So we destroyed the suspicious object in a contained blast. Evidence since recovered revealed their 'bomb' to have been little more than a stash of 'Boys and Girls' production reels wrapped in Vernon Kay's underpants. We weren't amused."

In spite of these efforts, viewing figures for the show have refused to lift, as surveys continue to show that few people with "any loose semblance of a life" are yet inclined to watch the show. In a move which has been described variously as "desperate", "futile" and "laughable", Mr Duncan Smith has at last been invited to join.

"When Christine Hamilton refused it was felt that there really wasn't any other choice," Channel Four executive Andy Peters explained. "On behalf of Channel Four I'd like to apologise in advance. I hope the viewers will forgive us."

Mr Duncan Smith quickly accepted the offer.

"It should be good for Iain," enthused a Conservative Party source. "He's never been the most interesting person in a room before - this should work wonders for his morale!"

Mr Duncan Smith's aunt agreed: "He's been so nervous since he got that job. He's painfully shy - hopefully this should bring him out of himself a bit! He really is a lovely young man."

It is believed that Mr Duncan Smith will take residence in the house at ten o'clock tonight in an hour long special to be televised live on E4, sponsored by a major manufacturer of sleeping tablets. Those without digital television will be able to catch the show on Channel Four later this week.

Observers agree that this may prove to be a critical stage in the beleaguered leader's battle for survival. "If he can't hold his own against a mob of uneducated, unintelligent and uninteresting slobs then he has no chance of beating Labour in the next election," commented DeadBrain's political editor, Douglas Ramsbottom.